Secure User Unit Data Search via Fingerprint Comparison
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Solution Overview
Problem
Existing methods for searching specific data in a user unit's memory either expose the data during the search process or allow malicious parties to verify the search method, compromising security, especially in applications requiring data secrecy.
Innovation Solution
A method and system using a processing key derived from a secret information via a key derivation function, combined with a secure communication channel, where the data is converted using a second one-way function before comparison, preventing exposure and verifiability, and ensuring secure data handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the specific datum is sent in clear to the user unit for searching, then the search process is simple and fast, but the data is exposed during the search process compromising security
Solution Approach 1:
The system performs preliminary conversion of the specific datum into a fingerprint using a one-way function before sending it to the user unit. This preliminary action ensures that the original data never appears in clear during transmission or storage, eliminating data exposure risk while maintaining search functionality through fingerprint comparison
Solution Approach 2:
The patent introduces a fingerprint as an intermediary representation of the original data. Instead of comparing original data directly, the system compares fingerprints generated by one-way functions. This intermediary allows search operations to proceed without exposing the sensitive original data, resolving the contradiction between search efficiency and data security
2Object-affected harmful factors
If a one-way function is used to convert data before searching, then data is not exposed during search, but malicious third parties can still verify whether data is stored by hashing and comparing
Solution Approach 1:
The patent moves the search operation to a different dimension by comparing fingerprints rather than original data. The one-way function transforms the problem from direct data comparison to fingerprint space comparison, making it computationally infeasible for malicious parties to reverse-engineer or verify stored data while maintaining search capability
Solution Approach 2:
The system replaces the mechanical approach of direct data comparison with a cryptographic substitution approach. Instead of comparing plaintext data directly, the patent uses one-way cryptographic functions to transform data into fingerprints, substituting the comparison mechanism to operate on transformed representations that prevent verification attacks
3Ease of operation
If the user unit stores and processes secret data, then the search functionality is available, but the user unit must be trusted which is not optimal from security point of view
Solution Approach 1:
The patent extracts the sensitive secret data from the user unit and keeps it exclusively in the central unit. Only the non-sensitive fingerprint representations are stored and processed in the user unit. This extraction eliminates the need for trusting the user unit with secret data while maintaining search functionality through fingerprint comparison operations
Data Source
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AI summary
The present invention concerns a method for searching for at least a specific datum among data stored in a permanent memory (14) of a user unit (11) linked to a central authority (10). This method comprises the following steps : - receiving in said user unit (11), a processing key (PK) derived, in said central authority (10), by means of a key derivation function applied on at least a secret piece of information, said key derivation function being a first iterative one-way function; - storing said processing key (PK) in a temporary memory (16) of the user unit (11); - receiving from said central authority (10), said at least one specific datum converted by a second one-way function using said processing key (PK); - in the user unit(11), converting at least a part of the data stored in the permanent memory (14) of the user unit, by said second one-way function and said processing key; - in the user unit (11), comparing said converted at least one specific datum received from the central authority (10) with the converted data from the permanent memory (14) of the user unit, thereby providing a search result; - deleting said processing key (PK) from the temporary memory (16) of the user unit (11). The present invention further concerns a system comprising a central authority (10) and at least a user unit (11), for implementing the method described above.